Illuminated dial



Dec. 14, 1965 D. E. PRQTZMANN ILLUMINATED DIAL Filed Dec. 15, 1964 2Sheets-Sheet 1 INVENTOR. Donald E. Profzmann AHys.

Dec. 14, 1965 D. E. PROTZMANN ILLUMINATED D lAL 2 Sheets-Sheet 2 FiledDec. 15, 1964 \AAAAA,

FIG. 5

45' FIG. 4

INVENTOR Donald E. Proizmann United States Patent ()fifice 3,223,833Patented Dec. 14, 19 65 3,223,833 ILLUMINATED DIAL Donald E. Protzrnann,Athens, Ga, assignor to General Time Corporation, New York, N.Y., acorporation of Delaware Filed Dec. 15, 1964, Ser. No. 418,495 6 Claims.(Cl. 240-6.43)

This application is a continuation-in-part of my copending applicationSerial No. 223,416, entitled Illuminated Dial, filed September 3, 1962.

The present invention relates generally to dial assemblies for clocks orother information displaying instruments and, more particularly, toilluminatable dials of this type.

It is a primary object of the present invention to provide anilluminatable dial assembly utilizing a single light source whichdevelops illumination completely around and across the dial displayfield without producing shadows from shafts and the like extendingthrough the dial. In this connection, it is an object of the inventionto provide such a dial assembly which permits a number of shafts toextend through the dial at a plurality of spaced points withoutproducing shadows from any of the shafts.

It is still another object of the invention to provide an illuminatabledial assembly of the above character which facilitates mounting of thedial assembly on its supporting plate. A related object is to providesuch an assembly which permits mounting pins or studs to be molded asintegral parts of the light-transmitting member.

A further object is to provide a dial assembly of the foregoing typewhich substantially increases the ratio of total dial area to lightedarea for rectangular dials.

A still further object of the invention is to provide a dial assembly ascharacterized above which provides increased flexibility in the designof the instrument with which the dial assembly is employed.

Another object is to provide such a dial assembly which is extremelyversatile with regard to the variety of illuminative and decorativeeffects which can be obtained by slight modifications in the basicstructure of the dial assembly.

Yet another object of the invention is to provide such a dial assemblywhich is inexpensive to manufacture and easy to install so as to besuitable for high volume production.

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings, in which:

FIGURE 1 is a transverse section through a typical clock embodying adial assembly of the present invention;

FIG. 2 is a perspective of the modified dial assembly employed in theclock illustrated in FIG. 1 with arrows showing the path of lighttransmission through the rim;

FIG. 3 is an end elevation view of the dial assembly of FIG. 2;

FIG. 4 is an enlarged fragment of the rim portion of the dial assemblyof FIGS. 1 through 3 with arrows indicating the direction of lighttransmission therethrough;

FIG. 5 is an enlarged section of a fragment of the face portion of thedial assembly of FIG. 1 with arrows indicating the direction of lighttransmission therethrough; and

FIG. 6 is an enlarged section of a fragment of the face portion of amodified dial assembly with arrows indicating the direction of lighttransmission therethrough.

While the invention will be described in connection with certainpreferred embodiments, it will be understood that I do not intend tolimit the invention to those embodiments. On the contrary, I intend tocover all alternatives, modifications and equivalents as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

Turning first to FIGURE 1, there is shown an information displayinginstrument taking the form of a clock 10 comprising a cover shell 11 andan illuminatable dial assembly 12 embodying the present invention.Included within the housing is a clock mechanism (not shown) mountedbetween a front frame plate 13 and a rear frame plate 14 spaced apart bypillars 15 and 16. The cover shell 11 is preferably generally cup shapedand is telescoped over the rear frame plate 14 and the clock mechanismso as to be supported by pillars 18 secured to the frame plate 14. Whenso supported, the shell 11 together with the dial assembly 12 form anattractive housing or case for the clock. An electric motor (not shown)is mounted within the housing and is coupled to a shaft at sleeve stack20 which supports the usual second, minute, and hour hands 21, 22 and23, respectively. The hands 21 through 23 sweep over a translucent clockdial plate 24 and are enclosed within a transparent lens 25. The lens25, the dial plate 24, and the front frame plate 13 are all held firmlynested together within a decorative bezel 26 which may be secured to theframe plate 13 by suitable retainer clips as described in US. Patent No.3,025,663 for example.

In accordance with the present invention the illuminatable dial assemblycomprises a member of light-transmitting material including a displayfield face portion having a pair of opposed side edges and a peripheralrim having a lamp receiving opening therein and a pair of opposed sideportions integral with the side edges of the face portion, the edges ofthe two side portions of the rim defining internally deflecting surfacesfor directing light from the lamp toward the face portion of theassembly in a direction substantially normal to the side edges of theface portion, the face portion being tapered in thickness inwardly fromthe two side edges so as to disperse light from the rim over the faceportion. Thus, the dial assembly 12 in the embodiment illustrated in thedrawings includes a cup-shaped member 30 of light-transmitting materialhaving a substantially flat, rectangular display field face 31 fromwhich light is dispersed and which is peripherally lighted by a singlelamp 32. Preferably, the member 30 is unitarily formed of clearpolystyrene or of an acrylic resin such as Lucite or Plexiglas. Themember 30 includes a generally U-shaped peripheral rim 33 which iscurved from the display field face 31 and formed with an aperture 34which receives the lamp 32. The lamp 32 may be mounted in a socketformed integrally with and within the clock housing. An illuminatedportion of the lamp 32 is alined with the side edges of the aperture 34so that light from the lamp is carried peripherally about the member 30within the rim 33.

In accordance with one aspect of the invention, the rim 33 includes apair of opposed, generally parallel side portions 41 and 42 which areintegral with the parallel side edges 43 and 44, respectively, of therectangular face 31. For the purpose of directing light from the lampopening 34 toward the face portion 31, the edges of the rim sideportions 41 and 42 are stepped or serrated so as to define internallyreflecting surfaces 45. In the illustrated embodiments, the reflectingsurfaces 45 are spaced evenly along the rim edge at 45 angles withrespect to lines 46 that are perpendicular to the display field face 31(see FIG. 4). The surfaces 45 all have approximately the same surfacearea and, as a result, the light traveling from the lamp 32 about therim 33 is reflected by the surfaces 45 so as to define a multiplicity oflight rays of approximately equal intensity which are transmittedthrough the rim portions 41 and 42 to the side edges 43 and 44,respectively, of the face 31. Because of the 45 angle disposition of thesurfaces 45, the light is reflected so that the rays moveperpendicularly toward the face 31 as indicated by the arrows 46a inFIG. 4.

The curved portion of each of the side edges 43 and 44 "of the member 30between the rim 33 and the display field face 31 has an outer radius 47(see FIG. 2) that is effective to channel light from the reflectingsurfaces 45 into the display 'field face portion 31, as indicated by thearrows 46b in FIG. 2. If the member 30 is formed of light-transmittingplastics of the type referred to above, this radius should be at leastthree times the thickness of the material so as to insure total internalreflection. This standard rule of thumb for light-conducting plasticsis, of course, also applicable to the curved corner portions -48 of therim 33.

In order to insure that the light from the lamp 32 is transmitted to thedisplay field face 31 along the entire length of each of the side edges43 and 44, the rim side portions 41 and 42 decrease in depth going awayfrom the lamp 32 (see FIG. 4) so that there is a path of solid materialfrom the lamp 32 to each of the reflecting surfaces 45, such as the path49 indicated in FIGURE 4 between the lamp 32 and the reflecting surface45'. It will be appreciated that the lamp 32 supplies light to theentire series of reflecting surfaces 45 on each rim side portion 41 and42.

To disperse the light from the reflecting surfaces 45 over the entirearea of the display field face 31 between the two side edges 43 and 44,the face portion 31 is tapered in thickness inwardly from each of thetwo side edges 43, 44. Preferably, the reflecting surface of the faceportion 31 is also serrated in parallelism wit-h the side edges 43 and44 to insure even distribution of the light across the entire area ofthe face 31. In the particular embodiment illustrated in FIGURES 1through 4, the back surface of the display field face 31 of the member30 slopes uniformly from each sideedge 43 and 44 toward a center line 50which represents the line of minimum thickness of the face 31. Thisuniform tapering results in light beams reflected forwardly from thedisplay field face 31 with substantially uniform intensity over theentire area of the translucent dial plate 24.

I One of the most important features of the dial assembly of thisinvention is that the light is transmitted inwardly toward the centerline 50 from opposite directions, i.e., from both the opposed side edges43 and 44 of the face 31. Consequently, it is possible to have shaftsfor switches, time sets, alarm sets and the like, such as the shaft 52in FIG. 1, extending through the dial along the center line 50 withoutproducing any shadows, since they are lighted from both sides. Moreover,since the light rays in the particular embodiment illustrated aredirected toward the center line 50 along generally parallel paths,rather than along radial paths toward a single center point for example,it is possible to form unlighted areas such as the plane-like sections53 and 54 at the edges of the conducting member 30 (see FIG. 2). Thesesections 53 and 54 may be utilized, for example, to support pins orstuds 55 (FIG. 3) for use in mounting the dial assembly on the clockmovement front plate or any other supporting plate. In one example ofthe invention, the pins or studs 55 are mounted as integral parts of thesections 53 and 54 so that the ends of the studs that protrude throughthe supporting plate may be heat crimped as a simple and inexpensivemeans of fastening. Furthermore, with the generally paralleltransmission of the light rays across the display field face 31, theplanar sections 53 and 54 may be open on three sides, as shown in FIG.2, so as to form pairs of unobstructed, opposed edges to furtherfacilitate the mounting and installation of the dial assembly.

In FIGURE 6, there is illustrated a fragment of a modified display fieldface for the cup-shaped dial assembly member 30. This display field face61 is similar to the face portion 31 previously described except thatthe in- 4 ward taper and the reflecting serrations are formed on theoutside rather than the inside surface of the display field face. Thisconstruction is adapted for use with an opaque dial 62 which is mountedon the back rather than the front of the light-transmitting member. Forexample, this construction is particularly effective for use withmulticolored printed paper dials. As illustrated in FIG. 6, the lightrays are reflected rearwardly against the dial 62 by the serrations 63and then are reflected forwardly again from the surface of the dial 62toward the viewer.

As can be seen from the foregoing detailed description, this inventionprovides an illuminatable dial assembly utilizing a single light sourcewhich develops illumination completely around and across the dialdisplay field without producing shadows from shafts or the likeextending through the dial. Since light is directed inwardly toward thecenter line of the display field face from opposed sides of the faceportion, a number of shafts can be projected through the dial at aplurality of spaced points without producing any shadows whatever.Furthermore, since the dial assembly of this invention permits mountingpins or studs to be formed at the edges of the display field face,mounting of the dial assembly on its supporting plate is greatlyfacilitated. Moreover, this invention provides increased flexibility inthe design of the instrument with which the subject dial assembly isemployed. For example, this dial assembly substantially increases theratio of total exposed dial area to lighted area for rectangular dials,since the illuminatable dial assembly may be formed with substantiallythe same configuration as that of the actual clock face. To light arectangular dial with a circular illuminatable assembly, it is necessaryto make the circular assembly of suflicient diameter to contain therectangular dial, thus wasting a considerable portion of the illuminatedarea. Similarly, the dial assembly of this invention is extremelyversatile with regard to the variety of illuminative and decorativeeffects which can be obtained by slight modifications in the basicstructure of the dial assembly. Finally, the dial assembly is alsoinexpensive to manufacture and easy to install so that it is speciallysuitable for high volume production.

I claim as my invention:

1. An illuminatable dial comprising a member of lighttransmittingmaterial including a display field face portion having a pair of opposedside edges, and a peripheral rim having a lamp receiving opening thereinand a pair of opposed side portions integral with said edges of saidface, the edges of the two opposed side portions of said rim defininginternally reflecting surfaces for directing light from said openingtoward the face portion of said member in a direction normal to saidside edges of the face, said face portion being tapered in thicknessinwardly from said opposed side edges so as to disperse light from thecorresponding side portions of said rim over said face.

2. An illuminatable dial comprising a member of lighttra'nsmittingmaterial including a display field face portion having a pair ofopposedside edges, and a peripheral rim having a lamp receiving opening thereinand a pair of opposed side portions integral with said side edges ofsaid face, the edges of said opposed side portions of said rim beingstepped so as to define internally reflecting surfaces for directinglight from said opening toward the face portion of said member in thedirection substantially parallel to said opposed side edges of saidface, said face portion being tapered in thickness inwardly from saidopposed side edges so as to disperse light from the corresponding sideportions of said rim over said face.

3. An illuminatable d-i al comprising a member of lighttransmittingmaterial including a display face portion having a pair of opposed sideedges, and a peripheral rim having a lamp receiving opening therein anda pair of opposed side portions integral with said side edges of saidface, the edges of thetwo opposed side portions of said rim defininginternally reflecting surfaces for directing light from said openingtoward the face portion of said member in a direction normal to saidside edges of the face, said face portion being tapered in thicknessinwardly from said opposed side edges and being serrated parallel tosaid side edges so as to disperse light from said side portions oversaid face.

4. An illuminatable dial comprising a member of light transmittingmaterial including a display face having a pair of substantiallyparallel opposed side edges, and a peripheral rim having a lampreceiving opening therein and a pair of substantially parallel opposedside portions integral with said side edges of said face portion, theedges of said opposed side portions of said rim being stepped so as todefine internally reflecting surfaces for directing light from saidopening toward the face portion of said member in a directionsubstantially normal to said opposed side edges of said face, said faceportion being tapered in thickness inwardly from said opposed side edgesand being serrated parallel to said side edges so as to disperse lightfrom said side portions over said face.

5. An illuminatable dial comprising a member of lighttransmittingmaterial having a generally quadrangular display field face portion, acontinuous rim having a lamp receiving opening therein and including apair of opposed side portions integral with a pair of opposed sides ofsaid quadrangular face portion, the edges of the two opposed sideportions of said rim being stepped so as 'to define internallyreflecting surfaces for directing light from said opening toward theface portion of said member in a direction substantially normal to saidopposed sides of said face portion, said face portion decreasing inthickness inwardly from said opposed sides of the face portion to a lineof minimum thickness extending between said opposed sides of said face,said face portion being provided with at least two openings for shaftson said line of minimum thickness.

6. An illuminatable dial comprising a member of lighttransmittingmaterial including a display face having a pair of substantiallyparallel opposed side edges, said face portion decreasing in thicknessinwardly from said side edges to a center line of minimum thicknessextending substantially parallel to said side edges, and a peripheralrim having a lamp receiving opening therein and a pair of substantiallyparallel opposed side portions integral with said side edges of the faceportion, the edges of the two opposed side portions of said rim defininginternally reflecting surfaces for directing light from said openingtoward said center line of said face from two opposite directions, thedecreasing thickness of said face portion serving to disperse light fromsaid rim over said face, said face portion being provided with openingsfor shafts on said center line whereby the light impinging on saidshafts from two opposite directions avoids the casting of shadows bysaid shafts.

References Cited by the Examiner UNITED STATES PATENTS 2,745,946 5/1956Protzman 240-1 X 2,831,453 4/1958 Hardesty 240-2.1 X 2,953,668 9/1960Bassett 240-1 X 2,965,749 12/1960 Hudson 240-1 3,029,334 4/ 1962Anderson et .al 240-1 3,043,947 7/ 1962 Albinger 240-1 LEO SMILOW,Primary Examiner.

1. AN ILLUMINATABLE DIAL COMPRISING A MEMBER OF LIGHTTRANSMITTING MATERIAL INCLUDING A DISPLAY FIELD FACE PORTION HAVING A PAIR OF OPPOSED SIDE EDGES AND A PERIPHERAL RIM HAVING A LAMP RECEIVING OPENING THEREIN AND A PAIR OF OPPOSED SIDE PORTIONS INTEGRAL WITH SAID EDGES OF SAID FACE, THE EDTES OF THE TWO OPPOSE SIDE PORTIONS OF SAID RIM DEFINING INTERNALLY REFLECTING SURFACES FOR DIRECTING LIGHT FROM SAID OPENING TOWARD THE FACE PORTION OF SAID MEMBER IN A DIRECTION NORMAL TO SAID SIDE EDGES OF 